Decarbonation process of carbonated materials

Abstract

The present invention relates to a process for the decarbonation of limestone, dolomite or other carbonated materials, said process comprising calcining particles of carbonated materials (6) in a reactor (8) of a first circuit (2) up to a temperature range in which carbon dioxide contained in the particles of carbonated materials (6) is released to obtain particles of decarbonated materials (16) and setting the dioxygen content supplied to the reactor (8) such that a first gas (14) exiting the reactor (8) and circulating in the first circuit (2), comprises at least 40% of CO2 by volume on a dry basis and less than 60% of CO2 by volume on a dry basis, while operating the reactor (8) under nominal condition, in particular non-starting condition.

Description

DECARBONATION PROCESS OF CARBONATED MATERIALSTechnical Field

[0001] The present invention relates to a decarbonation process of carbonated materials.Background Art

[0002] Traditionally, the decarbonation of limestone or dolomite is performed through calcination in a kiln.

[0003] The traditional kilns reject significant amounts of CO2 via the decarbonation of the carbonated materials and the combustion of fuels. In the search for cleaner industrial plants and cost saving in emerging markets that penalize carbon emissions, efforts have been made to reduce the CO2 footprint of kilns by introducing heat-regeneration measures. For instance, the air that is heated from product cooling is blown into the burning zone of the kiln and used for the combustion of the fuel. These improvements are required to achieve an efficiency with a specific heat input of <5.2GJ / Ton product. However, the CO2 generated in the known kilns is still emitted to the atmosphere as it cannot be used or sequestered because it is too diluted in the flue gas.

[0004] To overcome these drawbacks, the skilled person has come along with the concept of an electrically heated calciner as that disclosed in US 4,707,350, where limestone particles are entrained / conveyed by CO2 gas. The carbonated particles are first preheated before they are fed into a reactor where the decarbonation takes place under high temperatures. The decarbonation takes place in an atmosphere that is substantially free of nitrogen. The generated CO2 can be used or sequestered. However, the extended residence time of decarbonated particles in a CCh-rich atmosphere in a cooling zone positioned downstream from the decarbonation reactor causes recarbonatation of the product (i.e. lime), notwithstanding the fact that the electrically heated calciner disclosed in this patent requires heavy capex. WO2023 / 166464 discloses a calciner where limestone particles are entrained / conveyed by CO2 gas.Aims of the Invention

[0005] The invention aims to provide a solution to overcome at least one drawback of the teaching provided by the prior art.

[0006] More specifically, the invention aims to provide a process and a device for simplifying the operations and optionally allowing recovery of a maximum amount of CO2,more preferably to allow a decarbonation with a high production throughput of a product (e.g. quicklime, dolime) with a CCh-enriched exhaust stream, in particular a CCh-rich stream that is suitable for sequestration or use.Summary of the Invention

[0007] For the above purpose, the invention is directed to a process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, said process comprising the following steps: calcining particles of the carbonated materials in a reactor of a first circuit up to a temperature range in which carbon dioxide contained in the particles of the carbonated materials is released to obtain particles of decarbonated materials; conveying the particles of the carbonated materials by a first gas in the first circuit for preheating said particles; feeding the reactor with either a stream of a second gas comprising at least 25%, preferably at least 30%, more preferably at least 35% of dioxygen by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis, or a first stream of a second gas comprising at least 19%, preferably at least 25% of dioxygen by volume on dry basis and less than 45%, preferably less than 35% of dioxygen by volume on dry basis and a second stream of a third gas comprising at least 60% of dioxygen by volume on dry basis; transferring the particles of decarbonated materials to a cooling unit, preferably of a second circuit, in which the particles of decarbonated materials, preferably conveyed by the second gas, release a portion of their thermal energy to the second gas, more preferably said cooling unit comprising at least one suspension heat exchanger, in particular at least one cyclone; adjusting either the stream of a second gas or at least one of the first stream of a second gas and / or the second stream of a third gas, such that the first gas exiting the reactor, comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50%, more particularly less than 47% of CO2 by volume on a dry basis, preferably while operating the reactor under at least one of nominal condition and / or at least one of non-starting condition, non-shutdown condition and / or non-ramp up condition.

[0008] For the above purpose, the invention is also directed to a process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, said process comprising the following steps: -calcining particles of the carbonated materials in a reactor of a first circuit up to a temperature range in which carbon dioxide contained in said particles is released to obtain particles ofdecarbonated materials;- conveying the particles of the carbonated materials by a first gas in the first circuit for preheating said particles;- feeding the reactor with a stream of a second gas comprising at least 25%, preferably at least 30%, more preferably at least 35% of dioxygen by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis;- transferring the particles of decarbonated materials to a cooling unit, preferably of a second circuit, in which the particles of decarbonated materials preferably, conveyed by the second gas, release a portion of their thermal energy to the second gas, more preferably said cooling unit comprising at least one suspension heat exchanger, in particular at least one cyclone;- adjusting the stream of a second gas, such that the first gas exiting the reactor comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50%, more particularly less than 47% of CO2 by volume on a dry basis, preferably while operating the reactor under at least one of nominal condition and / or at least one of non-starting condition, nonshutdown condition and / or non-ramp up condition.

[0009] For the above purpose, the invention is also directed to a process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, said process comprising the following steps: -calcining particles of the carbonated materials in a reactor of a first circuit up to a temperature range in which carbon dioxide contained in said particles is released to obtain particles of decarbonated materials;- conveying the particles of the carbonated materials by a first gas in the first circuit for preheating said particles;- feeding the reactor with a first stream of a second gas comprising at least 19%, preferably at least 25% of dioxygen by volume on dry basis and less than 45%, preferably less than 35% of dioxygen by volume on dry basis and a second stream of a third gas comprising at least 60% of dioxygen by volume on dry basis;- transferring the particles of decarbonated materials to a cooling unit, preferably of a second circuit, in which the particles of decarbonated materials preferably, conveyed by the second gas, release a portion of their thermal energy to the second gas, more preferably said cooling unit comprising at least one suspension heat exchanger, in particular at least one cyclone;- adjusting at least one of the first stream of a second gas and / or the second stream of a third gas, such that the first gas exiting the reactor comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50%, more particularly less than 47% of CO2 by volume on a dry basis, preferably while operating the reactor under at least one of nominalcondition and / or at least one of non-starting condition, non-shutdown condition and / or non-ramp up condition.

[0010] According to specific embodiments of the invention, the process according to the invention comprises one or more of the following steps / features: separating at least some dinitrogen from the first gas in at least one CO2 filtration unit thereby forming a CO2 rich stream with a CO2 content of at least 80% by volume on dry basis, preferably at least 90% by volume on dry basis; purifying the first gas in a first of the at least one CO2 filtration unit thereby forming:- a CO2 partially enriched stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit comprises or consists of a membrane separation unit or a pressure swing apparatus, or- the CO2 rich stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit comprises or consists of an amine scrubber or a CO2 purification unit; a second of the at least one CO2 filtration unit comprises a membrane separation unit, said process further comprising purifying some or all of the CO2 partially enriched stream, in the membrane separation unit of the second of the at least one CO2 filtration unit, thereby forming a O2 rich stream and a CO2 concentrated stream; a third of the at least one CO2 filtration unit comprises a CO2 purification unit; purifying some or all of the CO2 partially enriched stream exiting the first of the of the at least one CO2 filtration unit and / or some or all of the CO2 concentrated stream exiting the second of the of the at least one CO2 filtration unit, in the CO2 purification unit of third of the at least one CO2 filtration unit, thereby forming the CO2 rich stream; mixing a substantially pure oxygen or a dinitrogen depleted air with air, thereby forming the second gas; forming the substantially pure oxygen with at least some the O2 rich stream; transferring the sensible heat of the particles of decarbonated materials in a heat exchanger to a heat transfer medium serving as a source of thermal energy, optionally converting at least some the thermal energy into mechanical energy, optionally converting at least some of the mechanical energy into electrical energy, supplying the at least one CO2 filtration unit with one of said thermal, mechanical and / or electrical energy;circulating the heat transfer medium in at least one of a heat recovery steam generator, an organic Rankine cycle apparatus and / or the amine scrubber; separating, preferably inertially separating, the particles of carbonated materials from the first gas and feeding the rector with the separated particles of carbonated materials in a pre-heating unit, preferably said pre-heating unit comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel; the first and second circuits are separated by selective separation means allowing the passage of solids while substantially preventing the passage of the first and second gases, preferably said means consisting in or comprising at least one element selected from the group consisting in a siphon element, a loop seal, single or multiple flaps, table feeder, cellular wheel sluice, fluid seal-pot, “Dollar” plate, or any of the following valves: rotary valves, cone valve, J valve, L valve, trickle valve and / or flapper valve; removing water from the first gas in a cooling unit of the first circuit, in particular a condenser or dryer; the reactor is a first reactor, preferably of a first group of reactors, preferably arranged in parallel, said process further comprising a step of extending decarbonation degree and / or adjusting the product reactivity, preferably (by) extending the retention time of the particles of decarbonated materials in a second reactor, preferably of a second group of reactors, more preferably arranged in parallel; the particles of decarbonated materials comprise at least 70% CaO by weight or at least 70% CaO and MgO by weight; heating the third gas via heat exchange with the second gas or in a cooling unit of a third circuit in which the particles of decarbonated materials conveyed by the third gas release a portion of their thermal energy to the third gas, preferably said cooling unit comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel; forming the third gas with at least some of the O2 rich stream;separating at least some dinitrogen from air in a gas separation system, preferably selected from the group comprising: a vacuum pressure separation absorption unit, a cryogenic unit or an air separation unit (ASU), thereby forming the dinitrogen depleted air; separating at least some dinitrogen from air in a gas separation system, preferably selected from the group comprising: a vacuum pressure separation absorption unit, a cryogenic unit or an air separation unit (ASU), and subsequently forming the second gas (14) with said dinitrogen depleted air; cooling the particles of decarbonated materials exiting the cooling unit of the second circuit or the heat exchanger to an ambient temperature in a water depleted gas atmosphere; wherein particles of the carbonated materials have a d90 less than 10 mm, preferably less than 6 mm, more preferably less than 4 mm, in particular less than 3 mm; the step of adjusting the stream of a second gas comprises adjusting the flow rate of the stream of a second gas and / or the Oxygen content of the stream of a second gas; the step adjusting at least one of the first stream of a second gas and / or the second stream of a third gas comprises adjusting at least one of the flow rate of the first stream of a second gas, the flow rate of the second stream of a third gas, the Oxygen content of the first stream of a second gas and / or the Oxygen content of the second stream of a third gas; the dioxygen content, calculated as a mass-flow-weighted average of the first and second streams, is at least 25%, preferably at least 30%, more preferably at least 35% by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis.

[0011] The invention is also directed to a process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite limestone, and hydration of decarbonated materials, said process comprising the steps of: -producing particles of the decarbonated materials using the process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, -hydrating at least some of the particles of the decarbonated materials exiting the cooling unit of the second circuit or the heat exchanger in a hydrationunit in presence of water.

[0012] The measures of the invention allow the kiln to operate with a lower concentration of CO2 in the exhaust gas, simplifying the design and operation in terms of avoiding air intake without having penalty in the overall process efficiency, considering the combination of the Ca / Mg carbonate calcination and related CO2 purification process.

[0013] The features of the invention allow for the recovery of almost all the emitted CO2 during the decarbonation (e.g. >80%, in particular >95%). Moreover, these measures result in a lower N2 concentration in the fumes leaving the calciner, which is beneficial for a membrane separation unit and optionally a CO2 Purification Unit (CPU) positioned downstream from the kiln. Compared to an “usual air fired” calciner with a similar capacity, the final fume flow can be reduced. Furthermore, the overall capital expenditure (Capex) is reduced due to limited modifications to existing calciner and possibly the use of a one- stage membrane concentration system.Brief Description of Drawings

[0014] Aspects of the invention will now be described in more details with reference to the appended drawings, wherein same reference numerals illustrate same features.

[0015] Figures 1 to 5 exhibit a first to fifth embodiments according to the invention.List of reference symbols2 First circuit, calcination circuit4 First (entraining) gas6 Carbonated particles8 Reactor / first reactor12 Second circuit14 Second gas16 Decarbonated particles18 Third gas20 Selective separation means, sealing device (optional)22 Cooling unit (a.k.a. cooling section) preferably of the second circuit32 Pre-heating unit (a.k.a. pre-heating section) of the first circuit81 Second reactor51 First separation unit / membrane separation unit61 Second separation unit / membrane separation unit71 CPU / CO2 purification unit81 Second reactorASU Air separation unitHE Heat exchanger (e.g. bulk solid heat exchanger)ORC Organic Rankine cycle apparatus / deviceG GeneratorDetailed description

[0016] The present invention will now be described in detail with reference to the accompanying drawings and their reference numbers, in which illustrative and non- limitative embodiments of the invention are shown.

[0017] As illustrated in Figure 1 , a first embodiment comprises a system for carrying out the method according to the invention. Particles of carbonated materials 6 such as limestone particles, in particular CaCOs fines are fed in a reactor 8 where they are exposed to a temperature range in which carbon dioxide contained in the carbonated materials 6 is released to obtain particles of decarbonated materials 16, preferably quicklime, in particular CaO. The particles of carbonated materials 6 are preheated before being fed to the reactor 8 though several heat suspension heat exchangers 32 (e.g. cyclones), while being conveyed by a first gas 4. The first gas 4 (a.k.a. exhaust gas) is formed with both the CO2 released during the decarbonation in the reactor 8 of the carbonated martials and the combustion of the fuel supplied in the reactor 8. The comburent of the combustion is typically an air enriched in dioxygen 14. The comburent is supplied by a second circuit 14. The decarbonated particles 16 exiting the reactor 8 are cooled by a flow of the air enriched in dioxygen 14 in several heat suspension heat exchangers 22 (e.g. cyclones) of a second circuit 12 allowing to cool the decarbonated particles 16 exiting the reactor at a high temperature. Figure 1 illustrates one column of cyclones 32 in the first circuit 2 and one column of cyclones 22 in the second circuit 12. The number of columns of cyclones can increased in at least one of the first circuit 12 and / or the second circuit 22 to cope with a larger flow rate.

[0018] The amount of dioxygen mixed with air is adjusted such that the first gas 4 exiting the reactor 8, comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50% of CO2 by volume on a dry basis. This range of CO2 is to be the result of a compromise between a reactor 8 operating with substantially pure oxygen and a “light” purification CO2 stage and a reactor 8 operating with air and a “complex” purification CO2 stage. Figure 1 , the system does not include one or more CO2 concentration units. Such a system can advantageously produce an exhaust gas suitable for soda applications with a CO2 concentration of around 40%volume dry basis, without significant operational limitations (e.g., controlling contaminant formation through regular maintenance). Depending on the fuel used, a condenser may be needed.

[0019] The present invention therefore overcomes a technical prejudice, namely in that a calciner should produce a CO2 concentrated fume (>90%) to ease the CO2 capture.

[0020] In figure 1 , all the carbonated materials 6 are preferably preheated only by the exhaust gas stream 4. The cooling stream 14 is preferably dedicated to cool only the calcined product 16 before said cooling stream 14 is fed in the reactor 8 as the sole or main comburent (a.k.a. oxidizer) of the reactor 8.

[0021] Figure 2 shows a second embodiment. The second embodiment differs from the first embodiment in that an exhaust gas treatment system is positioned downstream from the first circuit 2. The exhaust gas treatment system comprises a condenser or dryer for separating vapor form the exhaust gas 4. Typically the exhaust gas 4 is cooled in a condenser inducing a water condensation. The drops of water can be easily separated from the gas stream using usual techniques.

[0022] The exhaust gas 4 is then supplied to a first CO2 filtration unit 51 , a one stage membrane separation unit. Then, the exhaust gas is further filtered in a second CO2 filtration unit 71 , a CO2 purification unit (CPU).

[0023] The membrane separation unit 51 is arranged downstream from the calciner, allowing to reach a CO2 content (volume dry basis) of least 80%. A CO2 purification unit 71 is positioned downstream from the membrane separation unit 51 to increase the CO2 concentration in the exhaust gas to a value higher than 95%, preferably higher than 99% (dry volume) depending of the application, for instance. The membrane separation unit 51 (a.k.a. membrane filter) is adapted to separate the CO2 and O2 from the exhaust gas 4. The membrane of the filter is formed by example by the porous wall of inner tubes arranged in a conduct pipe. The porous walls of the inner tubes allow molecules such as O2, CO2, H2O with a higher rate of penetration to pass though the membrane pores compared to N2 molecules which do show a lower penetration rate. The gas molecule penetration rate depends on their size and diffusivity. As the membrane separation unit 51 also favours H2O separation compared to N2, it is preferable that most of H2O is removed from the exhaust gas prior to the membrane separation stage, justifying the presence of a condenser or dryer upstream. Even if the exhaust gas undergoes a first water separation in the condenser unit, an additional water removing step such as a molecular sieve dryer, could be provided upstream from the membrane separation unit toremove the water and obtain an exhaust gas substantially free of H2O before the membrane separation. This configuration is not illustrated. For this purpose, a membrane separation unit 51 can enclose this additional condenser to minimise the amount of water in the gas to be treated before the membrane stage separation. Alternatively, or complementary to the introduction of an additional condenser, the water separation efficiency of the condenser unit illustrated in Figure 2 can be increased.

[0024] Preferably, the CO2 purification unit (CPU) is configured to remove at least one of the following elements: acid gases, O2, Ar, CO, H2O, NOx, sulfur compounds, heavy metals, in particular Hg, Cd, and / or organic compounds, in particular CH4, benzene, hydrocarbons. More preferably, the CO2 purification unit is adapted to adjust the composition of the exhaust gas to the specification required by a carbon capture and utilization or carbon capture and storage application, preferably with a CO2 content above 90% (dry volume), more preferably above 95% (dry volume), in particular 99% (dry volume). Typically, a CO2 purification unit (CPU) relies on cryogenic separation allowing to reach a high CO2 purity. In the second embodiment, the CPU produces a concentrate of dioxygen that can be recycled in the reactor 8 as a comburent (not illustrated). Alternatively, to the second embodiment, the overall CO2 purification can be performed in a cryogenic separation unit, thereby excluding a membrane separation stage. However, such an approach requires more capital investment than the solution proposed in Figure 2. Other techniques to purify the CO2 can be applied such as pressure swing absorption unit and / or an amine wash unit. Nevertheless, the selection of a membrane separation unit, even a single stage separation unit appears not only particularly efficient in terms of capex and energy consumption but also appears particularly well suited for exhaust gas composition emitted by the reactor 8. Indeed, as the membrane separation favours separation of polar molecules (e.g., H2O, CO2) and O2 from N2, the treatment of an exhaust stream depleted in H2O and O2 would naturally lead to a CO2 enriched stream exiting the membrane separation unit.

[0025] The second embodiments also differs from the first embodiment in that a heat exchanger HE is provided to recover an excess heat still present in the decarbonated products 16 As the entire cooling flow 14 is used as a comburent, the flow for the cooling is limited, limiting the potential to extract calories from the calcined products 16. The remaining heat in the calcined products 16 can be collected in the heat exchanger HE. For instance a solid bulk heat exchanger can be advantageously selected. A solid bulk solid heat exchangers typically comprises a vessel or chamber containing a bed of solid particles through which a heat transfer medium flows. The solid particles act as a heattransfer medium, releasing heat as they come into contact with the fluid medium. Common types of bulk solid heat exchangers include: rotary drum dryers, fluidized bed heat exchangers (e.g. suspension heat exchanger in particular cyclone), plate heat exchangers for solids and screw conveyors. The heat is transferred to the fluid medium that can serves as a source of thermal energy, for instance, for an organic Rankine cycle OCR apparatus as illustrated in Figure 4 or a amine scrubber.

[0026] Figure 3 shows a third embodiment that differs from the second embodiment in that some dioxygen is also directly supplied to the reactor 8 so as to reach the right level of CO2 in the exhaust gas 4.

[0027] The third embodiment also differs from the second embodiment in a supplementary (second) reactor 81 that could be equipped, if required, with an additional heating source, such as oxyfuel burners or electrical heating means. This second reactor 81 is used to achieve a residual CO2 <2% in the product and to adjust the product reactivity. An additional benefit of the second reactor 81 is that the temperature and / or the residence time in the first calcination zone (first reactor 8) can be reduced compared to an embodiment without the second reactor 81 .

[0028] Figure 4 shows a fourth embodiment as illustrated in Figure 4 that differs from the second embodiment in that a second membrane separation 61 unit is foreseen. Thanks to this measure it is possible to separate some dioxygen content in the exhaust and to recycle the dioxygen into the second circuit 12 or the reactor 8. The demand of nitrogen depleted air from the air separation unit ASU can be reduced. Depending on the operating conditions, in particular when the dioxygen content in the exhaust gas 2 is low, the second membrane unit 61 can be bypassed and the gas treated by the first membrane separation unit is supplied directly to the CO2 purification unit CPU.

[0029] The fourth embodiment also differs from the second embodiment in that a second reactor 81 is provided. The second reactor 81 in the fourth embodiment presents the same advantages as those presented for the third embodiment.

[0030] The fourth embodiment also differs from the second embodiment in that the heat extracted by the heat exchange HE is transformed into electric energy via an organic Rankine cycle based machine driving a (electric) generator. This electric energy is used to ensure entirely or partially the energy requirement of the second separation membrane unit 61.

[0031] The fourth embodiment demonstrates the effective operation of a reactor 8 with an air partially enriched with dioxygen. Specifically, a decrease in the concentrationof CO2 in the exhaust stream from the reactor (compared to a situation where the exhaust stream is substantially pure in CO2) 8 can be offset by implementing an additional filtration step. The energy demand for this step can be, at least partly, met by utilizing the residual or waste heat present in the decarbonated material 16.

[0032] The fifth embodiment, as illustrated in Figure 5, differs from the first embodiment in that the number of cyclones present in the first 2 circuit (several heat suspension heat exchangers 32) and second 12 circuit (several heat suspension heat exchangers 22) are different and in that no selective separation means is provided between said circuits 2, 12. Also the reactor 8 is a typical flash calciner with a vertical tube fed at its lower end region with carbonated fines. Once, the carbonated fines enter in the tube, they are entrained by the ascending hot gas flow before being centrifugally separated in a dedicated cyclone. The hot gas flows is formed by burning fuel in the presence of a mix of air and dioxygen supplied by the second circuit. The fifth embodiment also differs from the first embodiment in that a second reactor 81 is present to control the product properties. Indeed, the second reactor 81 permits to control the residence time of the particles allowing to extend the calcination reaction and / or to modify the reactivity of the product by controlling a sintering process.

[0033] In the table below is illustrated how the CO2 content in the exhaust gas can be adjusted depending on the ratio between an air stream and the dioxygen flow.Table 1

[0034] The higher the amount of the dioxygen in the comburent the higher the CO2 concentration as less dinitrogen is fed in the reactor, leading to a lower dilution in the exhaust gas. A higher amount of dioxygen leads to a lower comburent flow rate andtherefore a lower cooling flow rate and hotter quicklime particles. A higher amount of dioxygen also leads to a lower exhaust temperature T2.

[0035] This table also shows that the range selected for CO2 concentration in the exhaust gas, namely at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50% of CO2, is also a compromise between optimizing heat recovery and energy demand for CO2 concentration purposes. Indeed, on one hand, an elevated CO2 concentration leads to an decrease of waste energy recovery (temperature of quicklime exiting the cooling unit of the second circuit increases due to a lower ratio of kg of cooling gas per kg of lime produced), while the demand for energy for the CO2 concentration apparatus decreases. On the other hand, a low CO2 concentration in the exhaust gas allows to increase the waste energy recovery in the kiln (temperature of quicklime exiting the cooling unit of the second circuit decreases) but leads to a higher energy demand for the CO2 concentration apparatus.

[0036] Advantageously, the system illustrated in Figure 5 can also be coupled to an exhaust gas treatment as disclosed in figures 2, 3 and 4 to increase the concentration of CO2 in the fumes.

[0037] The meaning of “substantially pure oxygen” in the present disclosure is an oxygen gas comprising at least 90 % (dry volume) dioxygen (i.e. O2), preferably at least 95% (dry volume) dioxygen (i.e. O2).

[0038] The meaning of “dioxygen enriched air” in the present disclosure is a gas composition comprising at least 21% of dioxygen, preferably at least 30%, more preferably at least 40% on a dry basis in volume. This composition can be obtain trough mixing air with substantially pure oxygen and / or a dinitrogen depleted air.

[0039] The meaning of “dinitrogen depleted air” is a gas composition comprising less than 79% of dinitrogen, preferably less than 70% of dinitrogen, more preferably less than 60% of dinitrogen on a dry basis in volume and / or at least 30% of dioxygen, preferably more than 40% of dioxygen. Such a gas composition can be obtained from an air separation unit (ASU), in particular pressure swing absorption unit.

[0040] The particles of the carbonated materials have a d90 less than 10 mm, preferably less than 6 mm, more preferably less than 4 mm, in particular less than 3 mm.

[0041] By mineral carbonate is meant a material selected from the list comprising limestone, dolostone, carbonated lime, in particular carbonated hydrated lime, and any combination thereof.

[0042] Embodiments as discussed above are defined by the following numbered clauses:A1. Process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, said process comprising the following steps:- calcining particles of the carbonated materials (6) in a reactor (8) of a first circuit (2) up to a temperature range in which carbon dioxide contained in the particles of the carbonated materials (6) is released to obtain particles of decarbonated materials (16);- conveying the particles of the carbonated materials (6) by a first gas (4) in the first circuit (2) for preheating the particles of the carbonated materials (6);- feeding the reactor (8) with either:- a stream of a second gas (14) comprising at least 25%, preferably at least 30%, more preferably at least 35% of dioxygen by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis, or- a first stream of a second gas (14) comprising at least 19%, preferably at least 25% of dioxygen by volume on dry basis and less than 45%, preferably less than 35% of dioxygen by volume on dry basis and a second stream of a third gas (18) comprising at least 60% of dioxygen by volume on dry basis,- transferring the particles of decarbonated materials (16) to a cooling unit (22), preferably of a second circuit (12), in which the particles of decarbonated materials (16), preferably conveyed by the second gas (14), release a portion of their thermal energy to the second gas (14), more preferably said cooling unit (22) comprising at least one suspension heat exchanger, in particular at least one cyclone;- adjusting either the stream of a second gas (14) or at least one of the first stream of a second gas (14) and / or the second stream of a third gas (18), such that the first gas (4) exiting the reactor (8), comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50%, more particularly less than 47% of CO2 by volume on a dry basis, preferably while operating the reactor (8) under at least one of non-starting condition, non-shutdown condition and / or non-ramp up condition, in particular while operating the reactor (8) under nominal condition.A2. Process according to Clause A1 , further comprising separating at least some dinitrogen from the first gas (4) in at least one CO2 filtration unit (51 ,61 ,71) thereby forming a CO2 rich stream with a CO2 content of at least 80% by volume on dry basis, preferably at least 90% by volume on dry basis.A3. Process according to the preceding clause, further comprising purifying the first gas (4) in a first of the at least one CO2 filtration unit (51) thereby forming:- a CO2 partially enriched stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit (51) comprises or consists of a membrane separation unit or a pressure swing apparatus, or- the CO2 rich stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit (51) comprises or consists of an amine scrubber or a CO2 purification unit.A4. Process according to the preceding clause, wherein a second of the at least one CO2 filtration unit (61) comprises a membrane separation unit, said process further comprising purifying some or all of the CO2 partially enriched stream, in the membrane separation unit of the second of the at least one CO2 filtration unit (61), thereby forming a O2 rich stream and a CO2 concentrated stream.A5. Process according to Clause A3 or A4, wherein a third of the at least one CO2 filtration unit (71) comprises a CO2 purification unit, said process further comprising purifying some or all of the CO2 partially enriched stream exiting the first (51) of the of the at least one CO2 filtration unit and / or some or all of the CO2 concentrated stream exiting the second (61) of the of the at least one CO2 filtration unit, in the CO2 purification unit of third of the at least one CO2 filtration unit (71), thereby forming the CO2 rich stream.A6. Process according to any of the preceding clauses, further comprising mixing at least one of a substantially pure oxygen or a dinitrogen depleted air with air, thereby forming the second gas (14).A7. Process according to the preceding clause in combination with Clause A4 or A5, further comprising forming the substantially pure oxygen with at least some the O2 rich stream.A8. Process according to any of the preceding clauses, further comprising transferring the sensible heat of the particles of decarbonated materials (16) in a heat exchanger (HE) to a heat transfer medium serving as a source of thermal energy, optionally converting at least some the thermal energy into mechanical energy, optionally converting at least some of the mechanical energy into electrical energy, supplying the atleast one CO2 filtration unit (51 , 61 , 71) with one of said thermal, mechanical or electrical energy.A9. Process according to the preceding clause, optionally in combination with Clause 3, further comprising circulating the heat transfer medium in at least one of a heat recovery steam generator (HRSG), an organic Rankine cycle apparatus (ORC) and / or the amine scrubber.A10. Process according to any of the preceding clauses, further comprising separating, preferably inertially separating, the particles of carbonated materials (6) from the first gas (4) and feeding the rector (8) with the separated particles of carbonated materials (6) in a pre-heating unit (32), preferably said pre-heating unit (32) comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel.A11. Process according to any of the preceding clauses, wherein the first (2) and second circuits (12) are separated by selective separation means (20) allowing the passage of solids while substantially preventing the passage of the first and second gases (4, 14), preferably said means consisting in or comprising at least one element selected from the group consisting in a siphon element, a loop seal, single or multiple flaps, table feeder, cellular wheel sluice, fluid seal-pot, “Dollar” plate, or any of the following valves: rotary valves, cone valve, J valve, L valve, trickle valve and / or flapper valve.A12. Process according to any of the preceding clauses, further comprising removing water from the first gas (4) in a cooling unit of the first circuit (2), in particular a condenser or dryer.A13. Process according to any of the preceding clauses, wherein the reactor (8) is a first reactor (8), preferably of a first group of reactors, preferably arranged in parallel, said process further comprising a step of extending decarbonation degree and / or adjusting the product reactivity, preferably extending the retention time of the particles of decarbonated materials (16) in a second reactor (81), preferably of a second group of reactors, more preferably arranged in parallel.A14. Process according to any of the preceding clauses, wherein the particles of decarbonated materials (16) comprise at least 70% CaO by weight or at least 70% CaO and MgO by weight.A15. Process according to any of the preceding clauses, further comprising heatingthe third gas (18) via heat exchange with the second gas (14) or in a cooling unit of a third circuit in which the particles of decarbonated materials (16) conveyed by the third gas (18) release a portion of their thermal energy to the third gas (18), preferably said cooling unit comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel.A16. Process according to Clause A4 in combination with any of Clauses A5 to A15, further comprising forming the third gas (18) with at least some of the O2 rich stream.A17. Process according to any of the preceding clauses, further comprising separating at least some dinitrogen from air in a gas separation system, preferably selected from the group comprising: a vacuum pressure separation absorption unit, a cryogenic unit or an air separation unit (ASU), thereby forming the dinitrogen depleted air.A18. Process according to any of Clauses A1 to A5 and A7 to A16 further comprising separating at least some dinitrogen from air in a gas separation system, preferably selected from the group comprising: a vacuum pressure separation absorption unit, a cryogenic unit or an air separation unit (ASU), and subsequently forming the second gas (14) with said dinitrogen depleted air.A19. Process according to any of the preceding clauses, wherein particles of the carbonated materials (6) have a d90 less than 10 mm, preferably less than 6 mm, more preferably less than 4 mm, in particular less than 3 mm.A20. Process according to any of the preceding clauses, wherein the adjusting the stream of a second gas comprises adjusting the flow rate of the stream of a second gas and / or the Oxygen content of the stream of a second gas.A21. Process according to any of the preceding clauses, wherein the adjusting at least one of the first stream of a second gas and / or the second stream of a third gas comprises adjusting at least one of the flow rate of the first stream of a second gas, the flow rate of the second stream of a third gas, the Oxygen content of the first stream of a second gas and / or the Oxygen content of the second stream of a third gas.A22. Process according to any of the preceding clauses, further comprising cooling the particles of decarbonated materials (16) exiting the cooling unit (22) of the second circuit (12) or the heat exchanger (HE) to an ambient temperature in a water depleted gas atmosphere.A23. Process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite limestone, and hydration of decarbonated materials (16), said process comprising the steps of ;- producing particles of the decarbonated materials (16) using the process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, according to any of Clauses A1 to A21 .- hydrating at least some of the particles of the decarbonated materials (16) exiting the cooling unit (22) of the second circuit (12) or the heat exchanger (HE) in a hydration unit in presence of water.B1. Process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, said process comprising the following steps:- calcining particles of the carbonated materials (6) in a reactor (8) of a first circuit (2) up to a temperature range in which carbon dioxide contained in said particles (6) is released to obtain particles of decarbonated materials (16);- conveying the particles of the carbonated materials (6) by a first gas (4) in the first circuit (2) for preheating said particles (6);- feeding the reactor (8) with a stream of a second gas (14) comprising at least 25%, preferably at least 30%, more preferably at least 35% of dioxygen by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis,- transferring the particles of decarbonated materials (16) to a cooling unit (22), preferably of a second circuit (12), in which the particles of decarbonated materials (16) preferably, conveyed by the second gas (14), release a portion of their thermal energy to the second gas (14), more preferably said cooling unit (22) comprising at least one suspension heat exchanger, in particular at least one cyclone;- adjusting the stream of a second gas (14), such that the first gas (4) exiting the reactor (8), comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50%, more particularly less than 47% of CO2 by volume on a dry basis, while operating the reactor (8) under at least one of nominal condition and / or at least one of non-starting condition, non-shutdown condition and / or non-ramp up condition.B2. Process for the decarbonation of carbonated materials, preferably carbonatedminerals, in particular limestone and / or dolomite, said process comprising the following steps:- calcining particles of the carbonated materials (6) in a reactor (8) of a first circuit (2) up to a temperature range in which carbon dioxide contained in said particles (6) is released to obtain particles of decarbonated materials (16);- conveying the particles of the carbonated materials (6) by a first gas (4) in the first circuit (2) for preheating said particles (6);- feeding the reactor (8) with a first stream of a second gas (14) comprising at least 19%, preferably at least 25% of dioxygen by volume on dry basis and less than 45%, preferably less than 35% of dioxygen by volume on dry basis and a second stream of a third gas (18) comprising at least 60% of dioxygen by volume on dry basis;- transferring the particles of decarbonated materials (16) to a cooling unit (22), preferably of a second circuit (12), in which the particles of decarbonated materials (16) preferably, conveyed by the second gas (14), release a portion of their thermal energy to the second gas (14), more preferably said cooling unit (22) comprising at least one suspension heat exchanger, in particular at least one cyclone;- adjusting at least one of the first stream of a second gas (14) and / or the second stream of a third gas (18), such that the first gas (4) exiting the reactor (8), comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50%, more particularly less than 47% of CO2 by volume on a dry basis, while operating the reactor (8) under at least one of nominal condition and / or at least one of non-starting condition, non-shutdown condition and / or non-ramp up condition.B3. Process according to Clause B1 or B2, further comprising separating at least some dinitrogen from the first gas (4) in at least one CO2 filtration unit (51 ,61 ,71) thereby forming a CO2 rich stream with a CO2 content of at least 80% by volume on dry basis, preferably at least 90% by volume on dry basis.B4. Process according to the preceding clause, further comprising purifying the first gas (4) in a first of the at least one CO2 filtration unit (51) thereby forming:- a CO2 partially enriched stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit (51) comprises or consists of a membrane separation unit or a pressure swing apparatus, or- the CO2 rich stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit (51) comprises or consists of an amine scrubber or a CO2 purification unit.B5. Process according to the preceding clause, wherein a second of the at least one CO2 filtration unit (61) comprises a membrane separation unit, said process further comprising purifying some or all of the CO2 partially enriched stream, in the membrane separation unit of the second of the at least one CO2 filtration unit (61), thereby forming a O2 rich stream and a CO2 concentrated stream.B6. Process according to Clause B4 or B5, wherein a third of the at least one CO2 filtration unit (71) comprises a CO2 purification unit, said process further comprising purifying some or all of the CO2 partially enriched stream exiting the first (51) of the of the at least one CO2 filtration unit and / or some or all of the CO2 concentrated stream exiting the second (61) of the of the at least one CO2 filtration unit, in the CO2 purification unit of third of the at least one CO2 filtration unit (71), thereby forming the CO2 rich stream.B7. Process according to any of Clauses B1 to B6, further comprising mixing at least one of a substantially pure oxygen or a dinitrogen depleted air with air, thereby forming the second gas (14).B8. Process according to the preceding clause in combination with Clause B5 or B6, further comprising forming the substantially pure oxygen with at least some the O2 rich stream.B9. Process according to any of Clauses B1 to B8, further comprising transferring the sensible heat of the particles of decarbonated materials (16) in a heat exchanger (HE) to a heat transfer medium serving as a source of thermal energy, optionally converting at least some the thermal energy into mechanical energy, optionally converting at least some of the mechanical energy into electrical energy, supplying the at least one CO2 filtration unit (51 , 61 , 71) with one of said thermal, mechanical or electrical energy.B10. Process according to the preceding clause, optionally in combination with Clause B4, further comprising circulating the heat transfer medium in at least one of a heat recovery steam generator (HRSG), an organic Rankine cycle apparatus (ORC) and / or the amine scrubber.B11. Process according to any of Clauses B1 to B10, further comprising separating, preferably inertially separating, the particles of carbonated materials (6) from the first gas (4) and feeding the rector (8) with the separated particles of carbonated materials (6) in a pre-heating unit (32), preferably said pre-heating unit (32) comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series,said columns being arranged in parallel.B12. Process according to any of Clauses B1 to B11 , wherein the first (2) and second circuits (12) are separated by selective separation means (20) allowing the passage of solids while substantially preventing the passage of the first and second gases (4, 14), preferably said means consisting in or comprising at least one element selected from the group consisting in a siphon element, a loop seal, single or multiple flaps, table feeder, cellular wheel sluice, fluid seal-pot, “Dollar” plate, or any of the following valves: rotary valves, cone valve, J valve, L valve, trickle valve and / or flapper valve.B13. Process according to any of Clauses B1 to B12, further comprising removing water from the first gas (4) in a cooling unit of the first circuit (2), in particular a condenser or dryer.B14. Process according to any of Clauses B1 to B13, wherein the reactor (8) is a first reactor (8), preferably of a first group of reactors, preferably arranged in parallel, said process further comprising a step of extending decarbonation degree and / or adjusting the product reactivity, preferably by extending the retention time of the particles of decarbonated materials (16) in a second reactor (81), preferably of a second group of reactors, more preferably arranged in parallel.B15. Process according to any of Clauses B1 to B14, wherein the particles of decarbonated materials (16) comprise at least 70% CaO by weight or at least 70% CaO and MgO by weight.B16. Process according to any of Clauses B1 to B15, further comprising heating the third gas (18) via heat exchange with the second gas (14) or in a cooling unit of a third circuit in which the particles of decarbonated materials (16) conveyed by the third gas (18) release a portion of their thermal energy to the third gas (18), preferably said cooling unit comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel.B17. Process according to Clause B4 in combination with any of Clauses B6 to B16, further comprising forming the third gas (18) with at least some of the O2 rich stream.B18. Process according to any of Clauses B1 to B17, further comprising separating at least some dinitrogen from air in a gas separation system, preferably selected from the group comprising: a vacuum pressure separation absorption unit, a cryogenic unit or an air separation unit (ASU), thereby forming the dinitrogen depleted air.B19. Process according to any of Clauses B1 to B6 and B8 to B17 further comprising separating at least some dinitrogen from air in a gas separation system, preferably selected from the group comprising: a vacuum pressure separation absorption unit, a cryogenic unit or an air separation unit (ASU), and subsequently forming the second gas (14) with said dinitrogen depleted air.B20. Process according to any of Clauses B1 to B19, wherein particles of the carbonated materials (6) have a d90 less than 10 mm, preferably less than 6 mm, more preferably less than 4 mm, in particular less than 3 mm.B21. Process according to any of Clauses B1 to B20, wherein the adjusting the stream of a second gas comprises adjusting the flow rate of the stream of a second gas and / or the Oxygen content of the stream of a second gas.B22. Process according to any of Clauses B1 to B21 , wherein the adjusting at least one of the first stream of a second gas and / or the second stream of a third gas comprises adjusting at least one of the flow rate of the first stream of a second gas, the flow rate of the second stream of a third gas, the Oxygen content of the first stream of a second gas and / or the Oxygen content of the second stream of a third gas.B23. Process according to any of Clauses B2 to B22, wherein the dioxygen content, calculated as a mass-flow-weighted average of the first and second streams is at least 25%, preferably at least 30%, more preferably at least 35% by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis.B24. Process according to any of Clauses B1 to B23, further comprising cooling the particles of decarbonated materials (16) exiting the cooling unit (22) of the second circuit (12) or the heat exchanger (HE) to an ambient temperature in a water depleted gas atmosphere.B25. Process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite limestone, and hydration of decarbonated materials (16), said process comprising the steps of ;- producing particles of the decarbonated materials (16) using the process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, according to any of Clauses B1 to B23.- hydrating at least some of the particles of the decarbonated materials (16) exiting the cooling unit (22) of the second circuit (12) or the heat exchanger (HE) in a hydration unit in presence of water.C1 . Process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, said process comprising the following steps:- calcining particles of the carbonated materials (6) in a reactor (8) of a first circuit (2) up to a temperature range in which carbon dioxide contained in said particles (6) is released to obtain particles of decarbonated materials (16);- conveying the particles of the carbonated materials (6) by a first gas (4) in the first circuit (2) for preheating said particles (6);- feeding the reactor (8) with either:- a stream of a second gas (14) comprising at least 25%, preferably at least 30%, more preferably at least 35% of dioxygen by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis, or- a first stream of a second gas (14) comprising at least 19%, preferably at least 25% of dioxygen by volume on dry basis and less than 45%, preferably less than 35% of dioxygen by volume on dry basis and a second stream of a third gas (18) comprising at least 60% of dioxygen by volume on dry basis,- transferring the particles of decarbonated materials (16) to a cooling unit (22), preferably of a second circuit (12), in which the particles of decarbonated materials (16) preferably, conveyed by the second gas (14), release a portion of their thermal energy to the second gas (14), more preferably said cooling unit (22) comprising at least one suspension heat exchanger, in particular at least one cyclone;- adjusting either the stream of a second gas (14) or at least one of the first stream of a second gas (14) and / or the second stream of a third gas (18), such that the first gas (4) exiting the reactor (8), comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50% of CO2 by volume on a dry basis, while operating the reactor (8) under nominal condition.C2. Process according to Clause C1 , further comprising separating at least some dinitrogen from the first gas (4) in at least one CO2 filtration unit (51 ,61 ,71 )thereby forming a CO2 rich stream with a CO2 content of at least 80% by volume on dry basis, preferably at least 90% by volume on dry basis.C3. Process according to the preceding clause, further comprising purifying the first gas (4) in a first of the at least one CO2 filtration unit (51 ) thereby forming:- a CO2 partially enriched stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit (51 ) comprises or consists of a membrane separation unit or a pressure swing apparatus, or- the CO2 rich stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit (51 ) comprises or consists of an amine scrubber or a CO2 purification unit.C4. Process according to the preceding clause, wherein a second of the at least one CO2 filtration unit (61 ) comprises a membrane separation unit, said process further comprising purifying some or all of the CO2 partially enriched stream, in the membrane separation unit of the second of the at least one CO2 filtration unit (61 ), thereby forming a O2 rich stream and a CO2 concentrated stream.C5. Process according to Clause C3 or C4, wherein a third of the at least one CO2 filtration unit (71 ) comprises a CO2 purification unit, said process further comprising purifying some or all of the CO2 partially enriched stream exiting the first (51 ) of the of the at least one CO2 filtration unit and / or some or all of the CO2 concentrated stream exiting the second (61 ) of the of the at least one CO2 filtration unit, in the CO2 purification unit of third of the at least one CO2 filtration unit (71 ), thereby forming the CO2 rich stream.C6. Process according to any of Clauses C1 to C5, further comprising mixing at least one of a substantially pure oxygen or a dinitrogen depleted air with air, thereby forming the second gas (14).C7. Process according to the preceding clause in combination with Clause C4 or C5, further comprising forming the substantially pure oxygen with at least some the O2 rich stream.C8. Process according to any of Clauses C1 to C7, further comprising transferring the sensible heat of the particles of decarbonated materials (16) in a heatexchanger (HE) to a heat transfer medium serving as a source of thermal energy, optionally converting at least some the thermal energy into mechanical energy, optionally converting at least some of the mechanical energy into electrical energy, supplying the at least one CO2 filtration unit (51 , 61 , 71 ) with one of said thermal, mechanical and / or electrical energy.C9. Process according to the preceding clause, optionally in combination with Clause 3, further comprising circulating the heat transfer medium in at least one of a heat recovery steam generator (HRSG), an organic Rankine cycle apparatus (ORC) and / or the amine scrubber.C10. Process according to any of Clauses C1 to C9, further comprising separating, preferably inertially separating, the particles of carbonated materials (6) from the first gas (4) and feeding the rector (8) with the separated particles of carbonated materials (6) in a pre-heating unit (32), preferably said pre-heating unit (32) comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel.C11. Process according to any of Clauses C1 to C10, further comprising removing water from the first gas (4) in a cooling unit of the first circuit (2), in particular a condenser or dryer.C12. Process according to any of Clauses C1 to C11 , wherein the reactor (8) is a first reactor (8), said process further comprising a step of extending decarbonation degree and / or adjusting the product reactivity, preferably by extending the retention time of the particles of decarbonated materials (16) in a second reactor (81 ).C13. Process according to any of Clauses 1 to 12, wherein the particles of decarbonated materials (16) comprise at least 70% CaO by weight or at least 70% CaO and MgO by weight.C14. Process according to any of Clauses C1 to C13, further comprising heating the third gas (18) via heat exchange with the second gas (14) or in a cool-ing unit of a third circuit in which the particles of decarbonated materials (16) conveyed by the third gas (18) release a portion of their thermal energy to the third gas (18), preferably said cooling unit comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel.C15. Process according to Clause C4 in combination with any of Clauses C5 to C14, further comprising forming the third gas (18) with at least some of the O2 rich stream.

[0043] Although the present invention has been described and illustrated in detail, it is understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present invention being limited only by the terms of the appended claims or clauses.

Claims

CLAIMS1 . Process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, said process comprising the following steps:- calcining particles of the carbonated materials (6) in a reactor (8) of a first circuit (2) up to a temperature range in which carbon dioxide contained in said particles (6) is released to obtain particles of decarbonated materials (16);- conveying the particles of the carbonated materials (6) by a first gas (4) in the first circuit (2) for preheating said particles (6);- feeding the reactor (8) with a stream of a second gas (14) comprising at least 25%, preferably at least 30%, more preferably at least 35% of dioxygen by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis;- transferring the particles of decarbonated materials (16) to a cooling unit (22), preferably of a second circuit (12), in which the particles of decarbonated materials (16) preferably, conveyed by the second gas (14), release a portion of their thermal energy to the second gas (14), more preferably said cooling unit (22) comprising at least one suspension heat exchanger, in particular at least one cyclone;- adjusting the stream of a second gas (14), such that the first gas (4) exiting the reactor (8), comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50% of CO2 by volume on a dry basis, while operating the reactor (8) under nominal condition.

2. Process for the decarbonation of carbonated materials, preferably carbonated minerals, in particular limestone and / or dolomite, said process comprising the following steps:- calcining particles of the carbonated materials (6) in a reactor (8) of a first circuit (2) up to a temperature range in which carbon dioxide contained in said particles (6) is released to obtain particles of decarbonated materials (16);- conveying the particles of the carbonated materials (6) by a first gas (4) in the first circuit (2) for preheating said particles (6);- feeding the reactor (8) with a first stream of a second gas (14) comprising at least 19%, preferably at least 25% of dioxygen by volume on dry basis and less than 45%, preferably less than 35% of dioxygen by volume on dry basis and a second stream of a third gas (18) comprising at least 60% of dioxygen by volume on dry basis;- transferring the particles of decarbonated materials (16) to a cooling unit (22), preferably of a second circuit (12), in which the particles of decarbonated materials (16) preferably, conveyed by the second gas (14), release a portion of their thermal energy to the second gas (14), more preferably said cooling unit (22) comprising at least one suspension heat exchanger, in particular at least one cyclone;- adjusting at least one of the first stream of a second gas (14) and / or the second stream of a third gas (18), such that the first gas (4) exiting the reactor (8), comprises at least 35%, preferably at least 40%, more preferably at least 45% of CO2 by volume on a dry basis and less than 63%, preferably less than 60%, more preferably less than 55%, in particular less than 50% of CO2 by volume on a dry basis, while operating the reactor (8) under nominal condition.

3. Process according to Claim 1 or 2, further comprising separating at least some dinitrogen from the first gas (4) in at least one CO2 filtration unit (51 ,61 ,71) thereby forming a CO2 rich stream with a CO2 content of at least 80% by volume on dry basis, preferably at least 90% by volume on dry basis.

4. Process according to the preceding claim, further comprising purifying the first gas (4) in a first of the at least one CO2 filtration unit (51) thereby forming:- a CO2 partially enriched stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit (51) comprises or consists of a membrane separation unit or a pressure swing apparatus, or- the CO2 rich stream and a CO2 depleted stream, in case the first of the at least one CO2 filtration unit (51) comprises or consists of an amine scrubber or a CO2 purification unit.

5. Process according to the preceding claim, wherein a second of the at least one CO2 filtration unit (61) comprises a membrane separation unit, said process further comprising purifying some or all of the CO2 partially enriched stream, in the membrane separation unit of the second of the at least one CO2 filtration unit (61), thereby forming a O2 rich stream and a CO2 concentrated stream.

6. Process according to Claim 4 or 5, wherein a third of the at least one CO2 filtration unit (71) comprises a CO2 purification unit, said process further comprising purifying some or all of the CO2 partially enriched stream exiting the first (51) of the of the at least one CO2 filtration unit and / or some or all of the CO2 concentrated stream exiting the second (61) of the of the at least one CO2 filtration unit, in the CO2 purification unit of third of the at least one CO2 filtration unit (71), thereby forming the CO2 rich stream.

7. Process according to any of the preceding claims, further comprising mixing at least one of a substantially pure oxygen or a dinitrogen depleted air with air, thereby forming the second gas (14).

8. Process according to the preceding claim in combination with Claim 5 or 6, further comprising forming the substantially pure oxygen with at least some the O2 rich stream.

9. Process according to any of the preceding claims, further comprising transferring the sensible heat of the particles of decarbonated materials (16) in a heat exchanger (HE) to a heat transfer medium serving as a source of thermal energy, optionally converting at least some the thermal energy into mechanical energy, optionally converting at least some of the mechanical energy into electrical energy, supplying the at least one CO2 filtration unit (51 , 61 , 71) with one of said thermal, mechanical and / or electrical energy.

10. Process according to the preceding claim, optionally in combination with Claim 4, further comprising circulating the heat transfer medium in at least one of a heat recovery steam generator (HRSG), an organic Rankine cycle apparatus (ORC) and / or the amine scrubber.11 . Process according to any of the preceding claims, further comprising separating, preferably inertially separating, the particles of carbonated materials (6) from the first gas (4) and feeding the rector (8) with the separated particles of carbonated materials (6) in a pre-heating unit (32), preferably said pre-heating unit (32) comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel.

12. Process according to any of the preceding claims, further comprising removing water from the first gas (4) in a cooling unit of the first circuit (2), in particular a condenser or dryer.

13. Process according to any of the preceding claims, wherein the reactor (8) is a first reactor (8), said process further comprising a step of extending decarbonation degree and / or adjusting the product reactivity, preferably by extending the retention time of the particles of decarbonated materials (16) in a second reactor (81).

14. Process according to any of the preceding claims, wherein the particles of decarbonated materials (16) comprise at least 70% CaO by weight or at least 70% CaO and MgO by weight.

15. Process according to any of the preceding claims, further comprising heating the third gas (18) via heat exchange with the second gas (14) or in a cooling unit of a third circuit in which the particles of decarbonated materials (16) conveyed by the third gas (18) release a portion of their thermal energy to the third gas (18), preferably said cooling unit comprising at least one suspension heat exchanger, in particular at least one cyclone, more preferably at least two cyclones arranged in series forming a column of cyclones, in particular at least two columns of cyclones, each column comprising at least two cyclones arranged in series, said columns being arranged in parallel.

16. Process according to Claim 5 in combination with any of Claims 6 to 15, further comprising forming the third gas (18) with at least some of the O2 rich stream.

17. Process according to any of Claims 2 to 16, wherein the dioxygen content, calculated as a mass-flow-weighted average of the first and second streams, is at least25%, preferably at least 30%, more preferably at least 35% by volume on dry basis and less than 57%, preferably less than 55%, more preferably less than 50%, in particular less than 45% of dioxygen by volume on dry basis.

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